feat(bokeh): implement venn-basic (#2471)

## Implementation: `venn-basic` - bokeh

Implements the **bokeh** version of `venn-basic`.

**File:** `plots/venn-basic/implementations/bokeh.py`

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20584330248)*

---------

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Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

plots/venn-basic/implementations/bokeh.py

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+""" pyplots.ai
+venn-basic: Venn Diagram
+Library: bokeh 3.8.1 | Python 3.13.11
+Quality: 90/100 | Created: 2025-12-29
+"""
+
+import numpy as np
+from bokeh.io import export_png
+from bokeh.models import HoverTool, Label
+from bokeh.plotting import figure, output_file, save
+
+
+# Data - Three sets representing product feature categories
+set_labels = ["Product A", "Product B", "Product C"]
+set_sizes = [100, 80, 60]  # Total sizes
+# Overlaps: AB=30, AC=20, BC=25, ABC=10
+only_a = 100 - 30 - 20 + 10  # 60
+only_b = 80 - 30 - 25 + 10  # 35
+only_c = 60 - 20 - 25 + 10  # 25
+only_ab = 30 - 10  # 20
+only_ac = 20 - 10  # 10
+only_bc = 25 - 10  # 15
+abc = 10
+
+# Circle parameters for 3-set Venn diagram
+radius = 0.35
+centers = [
+    (-0.2, 0.15),  # A - top left
+    (0.2, 0.15),  # B - top right
+    (0.0, -0.2),  # C - bottom center
+]
+
+# Create figure with proper sizing and hover tool
+p = figure(
+    width=4800,
+    height=2700,
+    title="venn-basic · bokeh · pyplots.ai",
+    x_range=(-1, 1),
+    y_range=(-0.8, 0.8),
+    tools="hover",
+    toolbar_location=None,
+)
+
+# Colors with transparency
+colors = ["#306998", "#FFD43B", "#4DAF4A"]  # Python Blue, Python Yellow, Green
+alpha = 0.4
+
+# Generate circle points inline (KISS - no helper function)
+n_points = 100
+theta = np.linspace(0, 2 * np.pi, n_points)
+
+# Draw the three circles as patches with hover tooltips
+for i, (cx, cy) in enumerate(centers):
+    x_pts = (cx + radius * np.cos(theta)).tolist()
+    y_pts = (cy + radius * np.sin(theta)).tolist()
+    p.patch(
+        x_pts,
+        y_pts,
+        fill_color=colors[i],
+        fill_alpha=alpha,
+        line_color=colors[i],
+        line_width=4,
+        line_alpha=0.8,
+        name=f"set_{i}",
+    )
+
+# Configure hover tool for interactivity
+hover = p.select({"type": HoverTool})
+hover.tooltips = [("Set", "@name"), ("Region", "Hover over numbers for details")]
+hover.mode = "mouse"
+
+# Add set labels with total sizes outside circles
+label_positions = [
+    (-0.55, 0.50, set_labels[0], f"n={set_sizes[0]}"),  # A - top left
+    (0.55, 0.50, set_labels[1], f"n={set_sizes[1]}"),  # B - top right
+    (0.0, -0.62, set_labels[2], f"n={set_sizes[2]}"),  # C - bottom
+]
+
+for lx, ly, text, size_text in label_positions:
+    label = Label(
+        x=lx,
+        y=ly,
+        text=text,
+        text_font_size="32pt",
+        text_font_style="bold",
+        text_align="center",
+        text_baseline="middle",
+        text_color="#333333",
+    )
+    p.add_layout(label)
+    # Add set size below the label
+    size_label = Label(
+        x=lx,
+        y=ly - 0.08,
+        text=size_text,
+        text_font_size="24pt",
+        text_align="center",
+        text_baseline="middle",
+        text_color="#666666",
+    )
+    p.add_layout(size_label)
+
+# Add region counts
+# Positions for each region (calculated manually for clarity)
+region_labels = [
+    # (x, y, count, description)
+    (-0.35, 0.25, str(only_a), "Only A"),  # Only A
+    (0.35, 0.25, str(only_b), "Only B"),  # Only B
+    (0.0, -0.38, str(only_c), "Only C"),  # Only C
+    (0.0, 0.28, str(only_ab), "A∩B"),  # A ∩ B only
+    (-0.18, -0.08, str(only_ac), "A∩C"),  # A ∩ C only
+    (0.18, -0.08, str(only_bc), "B∩C"),  # B ∩ C only
+    (0.0, 0.05, str(abc), "A∩B∩C"),  # A ∩ B ∩ C
+]
+
+for rx, ry, count, _desc in region_labels:
+    count_label = Label(
+        x=rx,
+        y=ry,
+        text=count,
+        text_font_size="36pt",
+        text_font_style="bold",
+        text_align="center",
+        text_baseline="middle",
+        text_color="#222222",
+    )
+    p.add_layout(count_label)
+
+# Style the figure - larger title for 4800x2700 canvas
+p.title.text_font_size = "48pt"
+p.title.align = "center"
+
+# Remove axes for cleaner look (Venn diagrams don't need axes)
+p.xaxis.visible = False
+p.yaxis.visible = False
+p.xgrid.visible = False
+p.ygrid.visible = False
+p.outline_line_color = None
+
+# Set background
+p.background_fill_color = "white"
+p.border_fill_color = "white"
+
+# Save as PNG and HTML
+export_png(p, filename="plot.png")
+output_file("plot.html", title="venn-basic · bokeh · pyplots.ai")
+save(p)

plots/venn-basic/metadata/bokeh.yaml

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+library: bokeh
+specification_id: venn-basic
+created: '2025-12-29T22:48:50Z'
+updated: '2025-12-29T23:04:45Z'
+generated_by: claude-opus-4-5-20251101
+workflow_run: 20584330248
+issue: 0
+python_version: 3.13.11
+library_version: 3.8.1
+preview_url: https://storage.googleapis.com/pyplots-images/plots/venn-basic/bokeh/plot.png
+preview_thumb: https://storage.googleapis.com/pyplots-images/plots/venn-basic/bokeh/plot_thumb.png
+preview_html: https://storage.googleapis.com/pyplots-images/plots/venn-basic/bokeh/plot.html
+quality_score: 90
+review:
+  strengths:
+  - Excellent visual clarity with well-chosen transparency (alpha=0.4) creating distinct
+    overlap colors
+  - Correct implementation of 3-set Venn diagram with accurate inclusion-exclusion
+    calculations
+  - Good use of Bokeh patch method for creating smooth circles
+  - Proper title format and clean layout without unnecessary axes/grid
+  - Interactive HTML output with hover tool
+  weaknesses:
+  - Set size labels (n=100, n=80, n=60) defined in code but not rendering visibly
+    in output image
+  - Hover tooltips could display actual region data instead of generic instructions